Cost effective second generation AC-modules: Development and testing aspects

In the framework of the European research project PV2GO, a new AC-module inverter was developed, taking into account all relevant aspects from a European market's point of view (standards, market, application, and research and development goals). The project goal was to achieve the overall system costs of 3 Euro per Wp for a modular plug-and-play photovoltaic system. For the photovoltaic-module, a standard 130-Wp Eurosolare module was chosen. The research and development (R&D) goal was to develop an advanced DC-control system consisting of a state-of-the-art programmable digital device and an Application Specific Integrated Circuit (ASIC) for the AC-control of the inverter. According to the topology concept, thermal and magnetic designs were optimized with regard to production technology and packaging for large-scale production. The new AC-modules were tested in a number of field-test sites in various parts of Europe and their reliability was assessed through Highly Accelerated Stress Tests. Efficiency and power quality have been tested in the laboratory. Further in the PV2GO project an optimization study of the manufacturing process of the new generation of AC-modules for high volume output was done. Another task was the pre-certification procedure to assure compliance with the European guidelines and standards.     

Hartstoffschichten für das Pressen und Prägen von Gläsern bei hohen Temperaturen

Hard and wear resistant coatings for the moulding and embossing of glasses at elevated temperatures Hard and wear resistant coatings of Titanium Aluminium Nitride TiAlN were deposited on various substrates by the application of different reactive deposition processes: RF-magnetron-sputtering, ion beam-sputtering and by the energetic cluster impact (ECI) process. The deposition of the coatings was performed under variation of biasing conditions and of process parameters such as pressures and flow rates of the process gases argon and nitrogen as well as of energies of species hitting the substrate surfaces. The microstructure particularly the growth morphology of several films was investigated by pictures of film cross sections recorded by transmission electron microscopy. Residual intrinsic film stresses were analyzed by measuring deflections of substrates in an interference optical microscope before and after the deposition of the coatings. By heating coated substrates and in-situ observation of deflections at elevated temperatures dependencies of thermally induced stresses on temperatures and variations of intrinsic stresses due to changes within the films could be analyzed and related to microstructure and growth conditions. In the paper specific characteristics of the deposition processes occuring on the scale both of atoms and of clusters which may contain several thousand of atoms are described and related to microstructure, residual stress states and damaging conditions. Different contributions to residual film stresses are analyzed on the base of theoretical considerations taking into account deposition kinetics and thermomecanical properties. The significance of achieved film properties for application, i. e. for the coating of tools for the manufacturing of optical components by moulding and embossing of glasses is discussed.     

Modulation of the allergic immune response in BALB/c mice by subcutaneous injection of high doses of the dominant T cell epitope from the major birch pollen allergen Bet v 1

Several in vitro and in vivo studies indicate that application of high doses of dominant T cell epitopes can induce a state of antigen-specific non-responsiveness (anergy). In the present study, we developed a murine model of an allergic immune response to Bet v 1, the major birch pollen allergen. Mice were sensitized by injection of rBet v 1 and the allergic state was proven by the presence of allergen-specific IgE and positive immediate-type skin tests to Bet v 1. In epitope mapping experiments, an immunodominant T cell epitope of Bet v 1 in BALB/c mice was identified by the use of overlapping peptides. This peptide (BV 139) was subsequently employed for treatment. Two tolerization protocols were used: in one approach, the peptide was administered to naive mice before immunization (group BV139-S), in the second, already sensitized mice were treated (S-BV139). The results demonstrated that administering high doses of the dominant T cell epitope of Bet v 1 profoundly diminished T cell proliferation to the peptide in the BV139-S group, and to the peptide as well as to the whole protein in the S-BV139 group. Skin test reactivity to Bet v 1 was reduced in the BV139-S group. However, no differences in terms of specific antibody production between treated and untreated mice could be observed. This study provides evidence that administration of dominant T cell epitopes can down-regulate the allergen-specific T cell response. Proceeding on the assumption that the T lymphocyte response to allergens is crucial for the induction and maintenance of the allergic disease, a modulation of the immune response to allergens by treatment with T cell epitope peptides could represent a promising concept for immunotherapy in the future.     

Is there a role for continuation phase cognitive therapy for depressed outpatients?

Two pilot studies evaluated the rate of relapse or recurrence (i.e., major depressive disorder) after cognitive therapy (CT). Two sequential cohorts included outpatients who responded to acute phase CT (A-CT) and who agreed to monthly, treatment-free follow-up. In Study 1, the Kaplan-Meier technique estimated relapse and recurrence rates of 40% at 6 months, 45% at 8 months, 50% at 12 months, 67% at 18 months, and 74% at 24 months. In Study 2, responders to A-CT received 8 months (10 sessions) of continuation phase CT (C-CT). In Study 2, relapse or recurrence was 20% at 6 and 8 months, 27% at 12 months, and 36% at 18 and 24 months after A-CT. An exploratory log-rank test showed that relapse or recurrence-free survival was greater in Study 2 than in Study 1. If replicated, this result suggests that C-CT can reduce depressive relapse or recurrence. Alternative explanations are presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Outcome criteria in strabismus surgery

PURPOSE: The authors describe the first case of delayed antimetabolite-related corneal epithelial toxicity after trabeculectomy and its successful treatment with limbal stem cell transplantation. METHODS: A 73-year-old woman underwent trabeculectomy with intraoperative mitomycin C. After surgery she received six 5-mg injections of subconjunctival 5-fluorouracil (5-FU) adjacent to the bleb. RESULTS: The patient had a functioning trabeculectomy and clear cornea until 30 months after surgery, at which time she developed a nonhealing superior corneal epithelial defect. After 4 months of conservative medical management, an autologous limbal stem cell transplantation was performed. The epithelial defect resolved completely within 1 week of limbal stem cell transplantation. CONCLUSIONS: Delayed corneal epithelial toxicity may be a late complication of antimetabolite-augmented trabeculectomy.     

Monomer and amino resin modified tall oil fatty acid alkyds

Summary Monomer modified tall oil fatty acid trimethylolethane medium type of phthalic alkyds made by the High Polymer Alkyd Technique show improved properties in dry time, mar resistance, and flexibility as compared with monomer modified conventional prepared systems. Greater hardness, less color degradation, greater resistance to extended periods at high temperature, and alkali and detergent resistances result from the urea and melamine resin modifications of tall oil fatty acid High Polymer alkyds than is obtained with similarly modified conventional alkyds.     

Performance models of storage contention in cloud environments

We propose simple models to predict the performance degradation of disk requests due to storage device contention in consolidated virtualized environments. Model parameters can be deduced from measurements obtained inside Virtual Machines (VMs) from a system where a single VM accesses a remote storage server. The parameterized model can then be used to predict the effect of storage contention when multiple VMs are consolidated on the same server. We first propose a trace-driven approach that evaluates a queueing network with fair share scheduling using simulation. The model parameters consider Virtual Machine Monitor level disk access optimizations and rely on a calibration technique. We further present a measurement-based approach that allows a distinct characterization of read/write performance attributes. In particular, we define simple linear prediction models for I/O request mean response times, throughputs and read/write mixes, as well as a simulation model for predicting response time distributions. We found our models to be effective in predicting such quantities across a range of synthetic and emulated application workloads.     

Statistical relational learning of trust

The learning of trust and distrust is a crucial aspect of social interaction among autonomous, mentally-opaque agents. In this work, we address the learning of trust based on past observations and context information. We argue that from the truster’s point of view trust is best expressed as one of several relations that exist between the agent to be trusted (trustee) and the state of the environment. Besides attributes expressing trustworthiness, additional relations might describe commitments made by the trustee with regard to the current situation, like: a seller offers a certain price for a specific product. We show how to implement and learn context-sensitive trust using statistical relational learning in form of a Dirichlet process mixture model called Infinite Hidden Relational Trust Model (IHRTM). The practicability and effectiveness of our approach is evaluated empirically on user-ratings gathered from eBay. Our results suggest that (i) the inherent clustering achieved in the algorithm allows the truster to characterize the structure of a trust-situation and provides meaningful trust assessments; (ii) utilizing the collaborative filtering effect associated with relational data does improve trust assessment performance; (iii) by learning faster and transferring knowledge more effectively we improve cold start performance and can cope better with dynamic behavior in open multiagent systems. The later is demonstrated with interactions recorded from a strategic two-player negotiation scenario.